The present inventor and others have studied to collect and manage position information and so forth of a plurality of mobile devices and to provide a search service relating to the mobile devices. The mobile devices mentioned here are apparatuses, such as in-vehicle devices, cellular phones, or tablet-type terminals, and are principally mobile terminals having a communication function that takes advantage of a mobile communication network, or devices or persons carrying such a terminal. Examples of related art that takes advantage of position information include techniques disclosed in Japanese Laid-open Patent Publication No. 2001-175662 and Japanese Laid-open Patent Publication No. 2009-8684.